A General Mathematical Model for Beam and Plate Vibration in Bending Modes Using Lumped Parameters.

Abstract : The analytic method proposed in this paper solves for natural frequencies and mode shapes of distributed mass and stiffness systems such as beams and plates. The structure is divided into an equivalent system of discrete masses and springs. A schematic diagram can be built up to show the nature of each item affecting the system. Increased off-hand evaluation of design changes results. A group of simultaneous equations is made up from the discrete schematic system. These equations comprise the mathematical model of the system. The model does not account for any extensional deformation. Only bending is considered. The application of the method to shells and other curved plates is suggested when only bending modes need to be considered.